Suction box cover for a papermaking machine



July 26, 1966 E. J. JUSTUS 3,262,842

SUCTION BOX COVER FOR A PAPERMAKING MACHINE Filed Sept. 25, 1965 &/

lwulw INVENTOR. 'ajqar zZz/Zzezfasr United States Patent 3,262,842 SUCTION BOX COVER FOR A PAPERMAKING MACHINE Edgar J. Justus, Beloit, Wis., assignor to Beloit Corporation, Beloit, Wis., a corporation of Wisconsin Filed Sept. 25, 1963, Ser. No. 311,468 6 Claims. (Cl. 162-374) The present invention relates to improvements in suction flatboxes for paper machines.

More particularly the invention relates to an improved paper machine suction flatbox assembly having a suction box with means for draining white water and maintaining subatmospheric pressure within the box and a box cover formed of a plurality of independent blocks, such as of cylindrical shape, having a central vertical axis and being of uniform size and shape stacked with upper planar ends at right angles to the vertical axis and arranged in side-by-side adjoining abutting coacting mutually supporting relationship with their upper ends being coplanar defining a horizontal supporting surface and the lengths defining between. them downwardly extending vertical drainage passages for leading to the suction box.

A suction fiatbox cover provides a support for a travelling Fourdrinier wire or for a belt travelling thereover supporting-the wire. Because of the pressure differentials across the wire caused by the suction in the suction flatbox to dewater the web on the wire, the frictional losses are substantial and the fiatbox must provide a smooth planar upper surface which does not create unnecessary wear in the belt or the wire sliding over the top. The cover must also provide drainage spaces which do not plug and which afford rapid removal of the white water drained from the web above. The suction flatbox cover is a critical part of a paper machine and has heretofore generally required expensive machining and expensive manufacture for providing a cover of adequate support and having drainage passages.

Accordingly, an object of the present invention is to provide an improved suction fiatbox cover and a method of making the cover which affords considerable savings in covers heretofore available, provides improve-d drainage characteristics and can be [made easily with a saving in 'cost.

A further object of the invention is to provide an improved suction flatbox cover which provides a completely smooth uniform upper supporting surface of long wearing characteristics.

A still further object of the invention is to provide a suction flatbox cover and a method of making the cover of improved long wearing metal alloys utilizing commercially available stock material.

A still further object of the invention is to provide a suction flatbox cover having a drainage opening of improved shape for improved drainage characteristics.

Other objects, advantages and features will become more apparent with the teaching of the principles of the invention in connection with the disclosure of the preferred embodiments thereof in the specification, claims and drawings, in which:

FIGURE 1 is a side elevational schematic view of a Fourdrinier section of a paper making machine embody. ing suction fiatboxes constructed in accordance with the principles of the present invention;

FIGURE 2 is a fragmentary enlarged top plan view of a suction box and cover constructed according to the invention;

FIGURE 3 is a vertical sectional view taken substantially along line III-III of FIGURE 2;

FIGURE 4 is a vertical sectional view taken substantially along line IVIV of FIGURE 2;

FIGURE 5 is a fragmentary top plan view, similar to FISURE 2 but showing a modified form of the invention; an

FIGURE 6 is an elevational view showing stock material for illustrating a step in the method of the inventlon.

On the drawings:

FIGURE 1 illustrates a Fourdrinier section of a paper making machine with the paper web W formed on the upper surface of a travelling Fourdrinier wire 10. The looped wire is supported on a breast roll 11 and a couch roll 12. Paper stock is distributed on the upper surface from a headbox 13. The upper run of the wire is supported on table rolls 14 and suction fiatboxes 17, and the lower return run on return and guide rolls such as 15.

The suction fiatboxes 17 are provided with suitable means for removing the white water drained from the web W on the wire 10, and suitable means for maintaining a subatmospheric pressure in the boxes.

As illustrated in FIGURES 2 through 4, the suction boxes are provided with walls 18 supporting a unique top.

The top is formed of a plurality of independent blocks 19 shown as preferably being of uniform size and shape and stacked with upper planar ends 19a at right angles to their vertical axis lying in a common plane to provide a top supporting surface 24.

The individual blocks 19 are formed of lengths of stock which are arranged in a side-by-side or stacked relationship so that they are in adjoining abutting coacting mutually supporting relationship.

Each of the blocks, as illustrated in FIGURE 2, engages the block behind and ahead of it at 20 and 21, relative to the direction of wire travel. Each of the blocks also engages individual blocks at each side of it as shown at 22 and 23. The blocks will thus be supported in four opposing directions by adjoining blocks which will maintain them all in a position wherein their axes are parallel and their upper surfaces are accurately and positively coplanar.

The blocks may be suitably clamped or otherwise held together, such as by a small weld bead formed at their lower ends at the locations 20, 21, 22 and 23. The assembled blocks which provide the box cover are provided at their edges with suitable supporting means for carrying them on the box, and for example they may be welded to the sides 18 at each location where the blocks at the edge engage the side such as at locations 18a.

For aiding in supporting the span of assembled blocks over the top of the suction box a supporting framework may be provided beneath the blocks such as in the form of longitudinally extending rods 25. These rods should be arranged so as not to interfere with optimum drainage between the blocks, and the rods are illustrated as being tapered at their upper edge to form a peak 25a which engages the lower surface of the blocks at their point of contact with the blocks ahead of and behind each of them. As will be observed in FIGURE 2 the blocks are preferably arranged so as to form longitudinal rows and the supporting rods 25 will extend down the centers of the rows. The rods are suitably attached at their ends at locations 18b to the walls of the suction boxes to fix their position and provide support.

In the arrangement of blocks, drainage spaces 26 are formed therebetween leading downwardly into the suction box. These drainage openings are formed naturally by the shape of the blocks but afford a drainage passage or channel of an improved shape which begins at a peak (viewing the channel in the direction of wire travel) and widens at a progressively increasing rat to its maximum width and then begins to narrow at a progressively increasing rate to a peak. This shape drainage passage is advantageous since at its location of maximum width it drains substantially the entire width of the wire and each of the adjoining drainage passages are substantially contiguous at their locations of maximum width. This arrangement also assures minimum chance of the collection of pulp which does not flow downwardly with the white water.

FIGURE 5 illustrates another form of block wherein blocks 27 are of octagonal shape. This arrangement provides surface contact between adjacent blocks and the blocks are arranged in the same manner as the cylindrical blocks of FIGURES 2 through 4, being situated in rows and being in adjoining coacting abutting mutually supporting relationship with blocks at each side and ahead of and behind each of the blocks. The blocks are assembled in the manner illustrated and secured to each other such as by welding at their lower ends and/or supported on suitable framework structure or rods. At the edges the assembled blocks are secured to the Walls 29 of the suction box. Blocks of other numbers of sides may be used and these blocks may also be arranged so that their corners engage rather than their sides.

FIGURE 6 illustrates the original structure of stock material from which the blocks are made. The stock is preferably of a superior wearing alloy or a ceramic and material known to the trade as KT silicon carbide is preferred. Materials such as disclosed in US. Patent 3,067,816, issued to William E. Gould, may be used.

Such materials may be a self-bonded ceramic, such as high-density, self-bonded silicon carbide. It may be a ceramic-bonded ceramic, such as silicon nitride-bonded silicon carbide. Also suitable are the hard, dense, metalbonded ceramics, such as chromium-bonded alumina, and hard, dense impregnated ceramics, such as zirconium diboride impregnated with molybdenum disilicide. Other specific hard, dense ceramics which can be used include titanium carbide, boron carbide, tungsten carbide, zirconium carbide, titanium boride, zirconium boride, titanium nitride, zirconia, alumina, nitride-bonded silicon carbide, metal-bonded titanium carbide, and metal-bonded tungsten carbide.

The linear stock rods 31 are obtainable commercially at a relatively reasonable cost inasmuch as those rods are made commercially for various purposes. The rods are cut at right angles as illustrated by the cutting locations 30 to form individual lengths 32. The cuts are made so that at least one end is accurately and smoothly at right angles to the axis of the stock and this end will form the suction box upper supporting surface. The lengths are then stacked or arranged in the manner shown in FIG- URES 2 to 4 and maintained in their stacked assembly with a completely uniform coplanar upper surface. The upper surface may be additionally polished or finished after assemblage if desired.

In operation the assembled blocks 19 are held together positively in their coacting supporting relationship and support a travelling Fourdrinier wire or travelling belt moving over the top, providing drainage holes or openings 26 therebetween. The material, such as silicon carbide provides a superior wearing surface which is made without excessive cost and from commercially available stock material.

The drawings and specifications present a detailed disclosure of the preferred embodiments of the invention, and it is to be understood that the invention is not limited to the specific forms disclosed, but covers all modifications, changes and alternative constructions and methods falling within the scope of the principles taught by the invention.

I claim as my invention:

1. A suction box cover for a paper making machine, said cover including a planar Wire bearing surface, comprising in combination,

a plurality of members positioned in adjoining abutting coacting mutually supporting relationship,

each member being rigid elongated and having an axis parallel to its length,

said member symmetrical about all planes parallel to and passing through said axis,

said member having at least one end cut to form a plane surface perpendicular to said axis,

the greatest dimension of said member measured in a direction parallel to said axis being less than the least dimension of said cover measured in the plane of said bearing surface,

said axis of said members being positioned perpendicular to said bearing surface, and said plane surfaces of all of said members being coplanar to form said bearing surface.

2. A suction box cover in accordance with claim 1, wherein said members are cylindrical in shape.

3. A suction box cover in accordance with claim 1, wherein said members are octagonal in shape.

4. A suction box cover for a paper making machine, said cover including a planar wire bearing surface, comprising in combination,

a plurality of members positioned in adjoining abutting coacting mutually supporting relationship,

each member being rigid elongated and having an axis parallel to its length,

said member symmetrical about all planes parallel to and passing through said axis, said member having at least one end cut to form a plane surface perpendicular to said axis,

the greatest dimension of said member measured in a direction parallel to said axis being less than the least dimension of said cover measured in the plane of said bearing surface,

said axis of said members being positioned perpendicular to said bearing surface,

said members arranged in rows extending longitudinally in the direction of travel of the Fourdrinier wire passing over said suction box cover,

and said plane surfaces of all of said members being coplanar to form said bearing surface.

5. A suction box cover in accordance with claim 1, wherein said members are formed of silicon carbide.

6. A suction box cover for a paper making machine, said cover including a planar wire bearing surface, comprising in combination,

a plurality of members positioned in adjoining abutting coacting mutually supporting relationship,

each member being rigid elongated and having an axis parallel to its length,

said member symmetrical about all planes parallel to and passing through said axis, said member having at least one end cut to form a plane surface perpendicular to said axis,

the greatest dimension of said member measured in a direction parallel to said axis being less than the least dimension of said cover measured in the plane of said bearing surface,

said axis of said members being positioned perpendicular to said bearing surface,

said plane surfaces of all of said members being coplanar to form said bearing surface,

and a plurality of supporting rods extending beneath the members and having tapered upper surfaces terminating in a horizontal supporting edge engaging the lower ends of the members for supporting the members and providing a supporting surface of minimum area for affording maximum drainage past the rods.

(References on following page) i References Cited by the Examiner UNITED STATES PATENTS McAnulty et a1. 162-374 Robbins 162-374 Van Ryzin 162-374 Van Ryzin 162-374 Prevost 162-374 Gatke 162-374 Youngchild 162-374 6 3,022,821 2/1962 McArdle 162-374 3,067,816 12/1962 Gould "2162-374 FOREIGN PATENTS 5 495,535 11/1938 Great Britain. 770,832 3/1957 Great Britain.

DONALL H. SYLVESTER, Primary Examiner. 10 J. H. NEWSOME, Assistant Examiner. 

1. A SUCTION BOX COVER FOR A PAPER MAKING MACHINE, SAID COVER INCLUDING A PLANAR WIRE BEARING SURFACE, COMPRISING IN COMBINATION, A PLURALITY OF MEMBERS POSITIONED IN ADJOINING ABUTTING COATING MUTUALLY SUPORTING RELATIONSHIP, EACH MEMBER BEING RIGID ELONGATED AND HAVING AN AXIS PARALLEL TO ITS LENGTH, SAID MEMBER SYMMETRICAL ABOUT ALL PLANES PARALLEL TO AND PASSING THROUGH SAID AXIS, SAID MEMBER HAVING AT LEAST ONE END CUT TO FORM A PLANE SURFACE PERPENDICULAR TO SAID AXIS, THE GREATEST DIMENSION OF SAID MEMBER MEASURED IN A DIRECTION PARALLEL TO SAID AXIS BEING LESS THAN THE LEAST DIMENSION OF SAID COVER MEASURED IN THE PLANE OF SAID BEARING SURFACE, SAID AXIS OF SAID MEMBERS BEING POSITIONED PERPENDICULAR TO SAID BEARING SURFACE, AND SAID PLANE SURFACES OF ALL OF SAID MEMBERS BEING COPLANAR TO FORM SAID BEARING SURFACE. 